Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Wearable devices may be used to obtain information about the wearer's physical activity and/or health state. For example, a wearable device may include one or more motion sensors, such as an accelerometer or gyroscope, in order to detect movements of the wearer and determine the wearer's level of physical activity (e.g., in terms of steps taken or calories burned). Alternatively or additionally, a wearable device may include one or more biological sensors that measure biological parameters of the wearer. The measured biological parameters could include pulse rate, blood oxygenation (oximetry), blood pressure, skin temperature, galvanic skin response (GSR), or other parameters that may relate to the wearer's level of physical exertion.
Generally, wireless charging coils for devices such as mobile phones are planar. For wearable devices, however, it may be desirable for a charging coil and its corresponding housing to have a three-dimensional shape, where windings of the coil may match the shape of the non-planar housing.